Template Synthesis of a Heterostructured MnO₂@SnO₂ Hollow Sphere Composite for High Asymmetric Supercapacitor Performance

Abstract

We have designed a new type of heterostructured MnO 2 @SnO 2 hollow sphere composite. This particular hollow heterostructured structure material contains two parts: one is the MnO 2 hollow spheres and the other is the SnO 2 scattered nanoparticles on the surface of MnO 2 hollow spheres. The MnO 2 hollow spheres are the composite's "skeletons" and the SnO 2 scattered nanoparticles are the "muscle". MnO 2 hollow spheres can enhance the electrochemical effective area of the composites as the supporting role. The SnO 2 nanoparticles on the surface of MnO 2 hollow spheres have a synergistic effect with the "MnO 2 skeletons". This can affect the efficiencies of the charge transfer and mass transfer in the charge−discharge progress. Thereby, the heterostructured hollow sphere composite, possessing excellent cyclability, can deliver 541.6 F/g at 1 A/g. After 1500 cycles of testing at 2 A/g, the specific capacitance of the MnO 2 @SnO 2 hollow spheres still remains ∼498 F/g. The asymmetric electrochemical capacitor (AEC), which has a high energy density at a high power density, can be assembled by a MnO 2 @SnO 2 hollow sphere composite as the positive electrode and active carbon (AC) as the negative electrode.

Sodium Pre-Intercalation Based Na3-Δ-Mno2@Cc for High Performance Aqueous Asymmetric Super Capacitor: Joint Experimental and Dft Study

“…The CV curve developed a very small redox peak by escalating the potential range to 1.2 V. By further increasing the upper cutoff potential to 1.3 V, we observed a prominent couple of redox peaks at around ≈0.4 V. Upon further extending the potential window to 0-1.4 V, two pairs of redox peaks emerged, one at the lower potential range at about 0.4-0.6 V and the other at the higher potential range of about 0.8-1.2 V. The first redox peaks are due to the characteristic charge storage mechanism of MnO 2 by the intercalation and de intercalation of electrolytes on Na 3 -MnO 2 electrode 35,36 . However, the mechanism of the second redox peak differs from that of the first, as stated by Nawishta J. et al 37 and Gang L. et al 38 . The CV curve area of Na 3 -MnO 2 at 0-1.4 V potential window is much larger than that at 0-1.3 0-1.2, 0-1.1, and 0-1.0 V. A reversible redox reaction causes the current to rise at around 1.0 V. 39 .…”

Synthesis of Polyaniline@MnO2/Graphene Ternary Hybrid Hollow Spheres via Pickering Emulsion Polymerization for Electrochemical Supercapacitors

“…The specific capacitance of PANI@MnO 2 /GR HS (740.9 F g –1 ) was 5.3 times that of MnO 2 /GR (140.4 F g –1 ) and 2.2 times that of PANI@MnO 2 /GR 2D (340.4 F g –1 ), clearly demonstrating the great contribution of the ternary composite and the hollow structure to its greatly enhanced capacitance. Compared to the PANI@MnO 2 /GR 2D composite, the hollow structured PANI@MnO 2 /GR ternary composite possesses hollow interiors, which not only shorten the distance of ion transmission and thus facilitate the rapid ion diffusion/transport during the charge/discharge processes but also enlarge the contact area between electrolyte and electrode material and thus provide more active sites and enough space for the electrolytes . In addition, the hollow structure could accommodate volume variation during repeated long-term cycling and thus avoid the aggregation of active materials, resulting in high electrochemical performance as well as long-term stability …”

“…Compared to the PANI@MnO 2 /GR 2D composite, the hollow structured PANI@MnO 2 /GR ternary composite possesses hollow interiors, which not only shorten the distance of ion transmission and thus facilitate the rapid ion diffusion/transport during the charge/discharge processes 42 but also enlarge the contact area between electrolyte and electrode material and thus provide more active sites and enough space for the electrolytes. 43 In addition, the hollow structure could accommodate volume variation during repeated long-term cycling and thus avoid the aggregation of active materials, resulting in high electrochemical performance as well as long-term stability. 44 The specific capacitance of our PANI@MnO 2 /GR HS is superior to that of much of the previous literature (measured in a three-electrode system), which is listed in Table 2.…”

Interlayer Spacing-Controlled Na0.71Co0.96O2 with High Pseudocapacitance for Enhanced Sodium Storage

“…According to the Bragg law, the larger interplanar spacing of the crystal structure corresponds to the lower diffraction angle at a constant wavelength of X-ray. The fitted lattice parameters from the diffraction peaks of those samples listed in Table S1 demonstrate that when the ratio of sucrose reaches 10%, the corresponding cell volume (75.988 Å) and interplanar spacing (3.401 Å) of Na 0.71 Co 0.96 O 2 are the largest. The result is similar with that of one-plot comparison.…”

“…The rapid social economy development accompanied with increasing fossil fuel consumption gives rise to environmental pollution, which is harmful to human life. It is critical to explore a sustainable, environmentally friendly renewable energy system. − Recently, the lithium-ion battery has been widely used as a typical electronic energy storage system. However, the limited lithium resources on the Earth can impede its large-scale application in the future. , The low-cost and relatively high-safety sodium-ion batteries (SIBs) with a similar energy storage mechanism have attracted widespread attention as alternative energy storage systems. − …”